Etiology of rhizome rot of asparagus (Asparagus officinalis) in Atenco, Mexico State

Abstract

The objective of this research was to identify the causal agent of asparagus rhizome rot, as well as evaluate different inoculation methods and the severity of the isolates. Sampling was carried out in five producing plots Atenco, Edo. from Mexico. Five isolates of Fusarium spp. were selected. (one per plot) to perform pathogenicity tests. Three isolates were selected for their colonization characteristics for severity tests with different inoculation methods: Immersion for 12 h, immersion for 30 min and inoculation by contact with absorbent paper soaked in 1 mL of inoculum. Concentrations of 1x106 conidia mL-1 were used. 10 rhizomes were used per treatment and 10 rhizomes without inoculation. To determine the severity, photographs (in GIMP®) of the rhizome were analyzed seven days after inoculation. The isolates were molecularly identified with ITS4/ITS5, EF688/EF1521 and TUBT1/BT2B. Fusarium prolifetatum was morphologically and molecularly identified in the three isolates. The P3DR isolate was the most severe (14.6%), followed by P5DR (13.9%) and P1SIR (11.6%). The most effective inoculation method was immersion for 30 min. They were registered in the NCBI Gene Bank with accessions ON738484 (P3DR), ON973801 (P5DR) and ON738483 (P1SIR). This is the first report of F. prolifetatum in the Edo. from Mexico.